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| Titel |
Trends of coastal and oceanic ST along the Western Iberian Peninsula over the period 1975- 2006. |
| VerfasserIn |
F. Santos, M. Gómez-Gesteira, M. deCastro, I. Álvarez, M. C. Sousa |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250059988
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| Zusammenfassung |
| Temperature is observed to have different trends at coastal and oceanic locations
along the western Iberian Peninsula (from 43.25oN to 37.25oN and from 9.75ºW to
14.75ºW) from 1975 to 2006. This period corresponds with the last warming period in
the area under study. The analysis was carried out by means of the Simple Ocean
Data Assimilation (SODA) package. Reanalysis of ocean climate variability are
available at monthly scale with a horizontal resolution of 0.5oà 0.5o and a vertical
resolution of 40 levels which allows us to obtain information beneath the sea surface
levels (http://www.atmos.umd.edu/~ocean/). Only the first 21 vertical levels (from
5.0 m to 729.35 m) were considered since the most important changes in the heat
content observed in the world ocean during the last decades, correspond to the upper
700m (Levitus et al., 2009). Warming was observed to be considerably higher at
ocean locations than at coastal ones at the same latitude. This behavior is observed
throughout the water column. Ocean warming ranged from values on the order of
0.3 ºC dec-1 near surface to 0.1 ºC dec-1 at 500 m depth. On the contrary, the
coastal warming is much smaller, reaching values close to 0.2 ºC dec-1 near surface
and decreasing rapidly at values below 0.1 ºC dec-1 for depths on the order of 50
m. Actually, coastal warming is practically negligible under 50 m. The different
warming rates near coast and at ocean locations have been previously described
for SST by the authors (Santos et al, 2011, 2012). The weaker coastal warming
compared with the ocean warming at the same latitude was related to the presence of
coastal upwelling. Coastal upwelling is the most importing forcing mechanism in the
western coast of the Iberian Peninsula pumping cold water from below to near surface
layers. In this sense, the heat diffusion from the atmosphere is constrained to near
surface area by advection, which mixes deeper colder water with warmer surface
water.
The heat content anomaly was also calculated from 1975 to 2006 in terms of temperature
anomaly The heat content for the upper 700m, showed a sharp increase from coastal (0.46
Wm-2 at 9.75ºW) to ocean locations (1.59 Wm-2 at 12.25ºW). The heat content anomaly
shows a sharp trend increase ~1.1 Ã1018J dec-1at ocean locations and a smoother increase
~0.6Ã1018J dec-1 at coastal locations.
Levitus, S., J. I. Antonov, T. P. Boyer, R. A. Locarnini, H. E. Garcia, and A. V. Mishonov
(2009), Global ocean heat content 1955–2008 in light of recently revealed instrumentation
problems, Geophys. Res. Lett., 36, L07608, doi:10.1029/2008GL037155.
Santos F., Gomez-Gesteira, M., and deCastro, M., 2011. Coastal and Oceanic
SST variability along the western Iberian Peninsula. Continental shelf Research,
doi:10.1016/j.crs.2011.10.005
Santos F., Gomez-Gesteira, M., deCastro, M., and Álvarez, I., 2012. Differences in coastal
and oceanic SST trends due to the strengthening of coastal upwelling along the Benguela
Current System, Continental shelf Research 34, 79-86. doi: 10.1016/j.csr.2011.12.004. |
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